「社の中に松のろうかがあったなら」
この川柳はサラリ ーマン川柳のコンテストをもらいました。
=>What did the senryu got? Not the コンテスト, but the prize or something, right?
この川柳はサラリ ーマン川柳のコンテストで賞をもらいました。
「会社の中に松 のろうかがあったらと言っています。
私はこれからこの川柳 の歴史的背景の話をします。
=>I don't think you explain the senryu in general, but the the senryu above, so it is better to add この in the sentence. And I think you explain historical background, not the history.
1600徳川幕府の前に生まれま した。ずっと前できました。
The incident itself was in 1701, so 18世紀のはじめ is better.
Readers would probably misunderstand that the senryu was made back then, so I think it more reader-friendly to explain the senryu was based on the chushingura story.
松のろうか is a sort of symbol where even a patient young lord, Asano, wants to kill somebody, Kira, who insulting him.
The Japanese salaryman is still patient just wishing 松のろうか, but it is common to see someone frustrated or violence in the office anywhere in the world.